Being stuck at a red light isn’t just frustrating — it’s bad for your health. Drivers are exposed to more harmful pollutants when idling at intersections than when zooming along an open road, scientists report February 12 in Atmospheric Environment.

When cars and trucks burn fuel, they emit tiny pollutants that have been linked to heart and respiratory illness. To see whether intersections are hot spots for these nanoparticles, researchers drove in a six-kilometer loop through Guildford, England, and measured how the concentration of pollution changed along the route.

Though the drivers only spent roughly 2 percent of their time at stoplights, that time accounted for about 25 percent of their total exposure to pollutants. At intersections, the concentration of nanoparticles was up to 29 times as high as it was on uncongested stretches of road.

“You emit

This article is only available to Science News subscribers. Already a subscriber? Log in now. Or subscribe today for full access.